Baseball is a dynamic game. It is constantly evolving thanks to changing roles, rules and faces. The two roles that have undergone perhaps the most dramatic changes over the years are the starting pitcher and, in turn, the reliever.
It's no real secret that starting pitchers have taken a big step back in innings pitched over the decades. But how dramatic is this change, and why is it happening?
In the average major league bullpen in 2000, a pitcher was asked to pitch an average of 2.98 innings per game. In 2006, that number crept past three. Through August 18, 2008 that number had grown to 3.09. Since there are still nine innings in a game, this gradual increase in bullpen workload obviously means that starting pitchers are racking up fewer and fewer innings.
Of course, these recent trends are nothing compared to stark difference between a starter's role in the modern era and the 1970s.
Take as an example the 1975 Twins. Bert Blyleven led that team with twenty complete games. The next two pitchers in the rotation both had at least twelve. The remainder of the team's hurlers combined for ten complete games. That put the Twins' 1975 complete game total at 57. In 2007, Minnesota starters combined for only five complete games.
In 1975 the Twins' top five starting pitchers logged 63 2/3 more innings than the 2007 top five starters. Perhaps one of the largest reasons for this change is a fundamental difference in the way pitchers are taught to throw. There is a greater emphasis on pitch velocity and this can wear arms out more quickly. The methods of studying the game have improved with technology, and as such the modern pitcher is ever closer to maximizing his potential.
Pitching a baseball puts an incredible amount of strain on the arm. When you consider the force that goes into every pitch it's practically a minor miracle when a starting pitcher can go through a full season without a stint on the disabled list.
Injuries to pitchers are more pervasive now than they were in the '70s despite the decreased workload, seemingly indicating that today's pitchers are putting more strain on their arms than ever before.
Coupled with better pitching is improving batting. Better bats and equipment exist in this modern era as well as more advanced swings. Just look at Willie Mays and Barry Bonds. Mays didn't even wear batting gloves back in the '50s and '60s. Meanwhile, there were medieval jousters who wore less armor than Bonds. Shin and wrist guards, shoulder straps, and batting gloves were constantly on his person when he stepped to the plate in 2007. (And we're just talking about the external performance enhancers here...)
In 1975, the average major-league hitter batted .258 with a .327 on-base percentage and .374 slugging percentage. In 2007, those numbers were .268/.336/.423. Those are increases across the board, with a dramatic rise in power. With more runs being scored, managers will, naturally, pull starters from games faster.
Another thing that should be considered when comparing starters between these two eras is the division races. Back in the mid-70s there were only four divisions, two in each league. With six teams in each division there were always a number of teams that were considered "hopeless."
Take for example, the 1975 National League West. Cincinnati demolished that division, with second place Los Angeles twenty games behind. Sixth place Houston finished 43.5 games behind the Reds.
When faced with a deficit like that, it is unlikely the other teams in the NL West did everything possible to win. It stands to reason that they let their pitchers get in more work than normal because the games really weren't all that crucial.
But in today's era of six divisions and wild-card spots, there are generally at least six or seven teams in either league legitimately competing for a playoff spot throughout most of the year, adding increased importance to each game. Today's managers may be more compelled to remove a starter early on in order to utilize the more specialized bullpen roles.
This increased pressure to win also puts managers on the hot seat when it comes to keeping starting pitchers healthy. It may not be the case that 100 pitches in a game is the magical number limit that means the difference between a starter being healthy or at risk. Really, how convenient of a number is that? But it has become accepted as a common wisdom.
If a manager lets a starter throw 130 pitches in consecutive games only to see him go down with an arm injury later in the season, that skipper will be exposed to endless criticism and perhaps unemployment.
All of these factores help lead to a generally more conservative managerial approach when it comes to handling the modern starting pitcher. The Twins' bullpen has been worn thin this year, which has led to inconsistency and ineffectiveness, but that's hardly a trait unique to this team. Bullpens tend to receive considerably more work these days while starters are generally treated with extreme caution.
While broadcasting games on television, Blyleven frequently reminisces about the way the game used to be played, a tinge of disappointment in his voice over a perceived babying of today's starters. But whether the traditionalists like it or not, modern baseball is a game of specialized roles. And the role of a starting pitcher, it seems, is diminishing with each passing year.